#define _CRT_SECURE_NO_WARNINGS
#pragma warning(disable : 4996)
#pragma warning(disable : 6031)


#include <stdio.h>

int main() 
{
    int a, b, c, d;
    float sum;

    scanf("%d %d %d %d", &a, &b, &c, &d);
    sum = a * 0.2 + b * 0.1 + c * 0.2 + d * 0.5;

    printf("%.1f", sum);
    return 0;
}